The APOB Knouckout HAP1 Polyclonal Cells constitute a polyclonal knockout cell population generated by CRISPR/Cas9-mediated disruption of the APOB gene in the HAP1 human near-haploid cell line. This targeted gene disruption abolishes expression of apolipoprotein B (APOB), a critical structural component of very low-density lipoproteins (VLDL) and low-density lipoproteins (LDL). The polyclonal format provides a heterogeneous pool of edited cells, enabling robust loss-of-function studies without clonal isolation bottlenecks. The cells serve as a powerful tool for dissecting hepatic lipid export and receptor-mediated cholesterol uptake in a human genetic background.
The HAP1 host cell line is derived from the KBM-7 chronic myeloid leukemia cell line and exhibits a near-haploid karyotype. As an adherent, fibroblast-like cell line, HAP1 is widely used for functional genomics and CRISPR-based screens due to its haploid nature, which simplifies knockout generation and phenotypic analysis. This genetic simplicity makes it an ideal chassis for modeling gene function in lipid metabolism, where APOB plays a pivotal role. The human origin ensures physiological relevance for investigating lipoprotein biology and cholesterol homeostasis.
APOB encodes apolipoprotein B-100, the major structural protein of VLDL and LDL. Transcriptionally regulated by HNF4A, PPARA, and SREBF1 in response to insulin and dietary fatty acids, APOB interacts with MTTP for hepatic VLDL assembly and secretion. It serves as the high-affinity ligand for LDLR, mediating endocytosis of LDL and cholesterol delivery. It also interacts with APOE and heparan sulfate proteoglycans to modulate lipoprotein clearance. Downstream, cellular cholesterol regulates SREBF2 and HMGCR, controlling cholesterol synthesis. Thus, APOB integrates lipid transport, VLDL secretion, and cholesterol metabolism.
In the HAP1 near-haploid background, knockout of APOB creates a clean loss-of-function model that eliminates lipoprotein structural contributions without the complexity of diploid gene dosage effects. This system allows direct assessment of intracellular cholesterol handling, VLDL assembly defects, and LDLR-mediated uptake kinetics in a homogeneous human cell population. The haploid state enhances the utility of CRISPR screening approaches, enabling genome-wide modifier screens to identify genes that synergize with or bypass APOB deficiency. Consequently, these cells are valuable for dissecting genetic interactions in familial hypobetalipoproteinemia and hypercholesterolemia, as well as for evaluating lipid-modulating therapeutic candidates.
The APOB Knouckout HAP1 Polyclonal Cells are tailored for diverse research applications including lipoprotein metabolism studies, cardiovascular disease modeling, and drug screening for lipid-lowering agents. Researchers can validate knockout by Sanger sequencing and assess functional consequences via western blotting for APOB protein, RT-qPCR for APOB mRNA, ELISA for secreted APOB, fluorescent LDL uptake assays, and Oil Red O staining of neutral lipids. The cells are particularly suited for functional genomics of lipid transport and for high-throughput screens aimed at identifying novel regulators of hepatic lipid export. For additional details or to discuss custom projects, please contact Ascent Research.
